I've been watching some bleach and FMA endings and I thought, what if ash had 16 when he received his first pokemon, how much darker/serious would the series be? Pokemons would keep scars and there would be noticeable differences between male and female pokemon, and at least two of ash's pokemons would have died by now, mmmh starting to sound like a nuzlocke comic.
Anyway there were really only two hard parts to do here:
1) The running animation (20 hellish frames);
2) Timing the freaking thing, I couldn't find a song that lasted what I wanted so I had to cut some frames out.